package LinkList;

import java.util.List;

public class MyLinkList implements IList{

    static class ListNode{
        public int val;
        public ListNode prev;
        public ListNode next;

        public ListNode(int val){
            this.val = val;
        }

    }

    public ListNode head;
    public ListNode last;

    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);

        if (head == null){
            head = last = node;
        }else{
            node.next = head;
            head.prev = node;
            head = node;
        }
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);

        if (head == null){
            head = last = node;
        }else{
            last.next = node;
            node.prev = last;
            last = last.next;
        }
    }

    @Override
    public void addIndex(int index, int data) {
        if(index < 0 || index > size()){
            return;
        }
        if (index == 0){
            addFirst(data);
            return;
        }
        if (index == size()){
            addLast(data);
            return;
        }
        ListNode node = new ListNode(data);
        ListNode cur = findIndex(index);
        node.next = cur;
        cur.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;
    }

    private  ListNode findIndex(int index){
        ListNode cur = head;

        while(index!=0){
            cur = cur.next;
            index--;
        }
        return cur;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null){
            if (cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        ListNode cur = head;
        while (cur != null){
            if (cur.val == key){
                if(cur == head){
                    head = head.next;
                    if (head != null){
                        head.prev = null;
                    }
                }else{
                    cur.prev.next = cur.next;
                    if (cur.next == null){
                        last = last.prev;
                    }else{
                        cur.next.prev = cur.prev;
                    }
                }
            }
            return;
        }
        cur = cur.next;
    }

    @Override
    public void removeAllkey(int key) {
        ListNode cur = head;
        while(cur != null){
            if (cur.val == key){
                if (cur == head){
                    head = head.next;
                    if (head != null){
                        head.prev = null;
                    }
                }else{
                    cur.prev.next = cur.next;
                    if (cur.next == null){
                        last = last.prev;
                    }else{
                        cur.next.prev = cur.prev;
                    }
                }
            }
            cur = cur.next;
        }
    }

    @Override
    public int size() {
        int count = 0;
        ListNode cur = head;

        while (cur != null){
            count++;
            cur = cur.next;
        }
        return count;
    }

    @Override
    public void clear() {
        ListNode cur = head;
        while(cur != null){
            ListNode curN = cur.next;
            cur.prev = null;
            cur.next = null;
            cur = curN;
        }
        head = last = null;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while (cur != null){
            System.out.println(cur.val+" ");
            cur = cur.next;
        }
        System.out.println();
    }
}
